How Microsoft made the Touch Mouse

And how it could develop in the future

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Microsoft actually built a multi-touch mouse before Apple; at CES last year Stephen Bathiche, the head of the Microsoft Applied Sciences team, told TechRadar how his team designed a capacitive mouse and announced their research prototype at a conference a month before Apple announced the Magic Mouse.

The Microsoft hardware team has taken another year to turn that prototype into a mouse they're happy with, collaborating with researchers in the Applied Sciences team and the innovation development team at Microsoft Research in Cambridge (many of whom worked on projects like Microsoft Surface).

Hrvoje Benko of the Applied Sciences group showed TechRadar a selection of the prototypes from the three years he's been working on the 'Mouse 2.0' project. (Benko is behind the Lightspace project that uses a camera and projector "to make any surface, any wall - any body part! - into a Surface.")

CONCEPTS:Five different ideas for Mouse 2.0 - FITR mouse, Touch Mouse, the articulated franken-mouse, the hemisphere mouse and the mouse that shines a laser on your desk

The idea was to combine the good old mouse - which has been around since the early 1960s without much change in the way you use it - with the multi-touch features of Microsoft Surface. You can touch, grip and gesture with your whole hand, but the mouse reduces all your dexterity to a single cursor and right-click.

The Mouse 2.0 concepts went through several different kinds of touch sensors. A curved mouse made from acrylic sheet and an infrared camera (using the Frustrated Internal Total Reflection technique Perceptive Pixel uses for touch screens where the touch of a finger is detected because it allows reflected internal light out of the surface layer) looked good but could only sense the tips of your fingers.

Putting a diffused illumination infrared camera in a half sphere produced an unusual shape that had too much internal reflection and while it made users more creative in the way they used gestures it also made their hands get tired.

An articulated mouse made from the innards of two mice bolted together, with knobs for two of your fingers sticking out at the front, was accurate and comfortable - but only allowed two-touch gestures.

One design with an infrared laser and camera detected your fingers touching the desk surface around the mouse, but only worked well if it was just the right size for your hand.

More like a mouse

In the end, the team picked a multi-touch mouse using a capacitive sensor, because that lets you have gestures without abandoning the familiar mouse shape (the sensor is small and you don't need to fit in a camera; it's not too expensive, either, because it's printed onto plastic using conductive ink).

"The benefits of the mouse are that it's comfortable and precise," Benko told us. "We didn't want to come up with something that meant people have to change the way they use the mouse. You can still point and click."

But when you click, it's not a button that's moving; it's the whole mouse (and that's more to give you feedback than to detect the click). "The whole surface of the mouse is a button so when you right-click and left-click it's really the same - but we detect where you click and that's what determines the click," he explained.

PROTOTYPES:Some of the many stages of designing the Touch Mouse, from the 3D printed (but fully working) first CAD prototype to the almost-finished wireless mouse. The diamond pattern is the multi-touch sensor - which is covered in later prototypes

Clicking and gesturing on the mouse surface is very comfortable thanks to the textured surface, which is a grid of tiny laser-etched dots. "This mouse will be used a lot", boasts Benko, "so we used laser etching; you cannot rub this off."

The mouse has a matte surface on purpose. "We spent a lot of time optimising the surface top coat. It's not glossy - try moving your fingers on a glossy surface for more than a few minutes; it gets really tiring," he points out.

And the dots are there for two reasons. "They showcase where the sensor is, and they make the surface a little bumpy, so if you have oily fingers you can still make the gestures because it has some tactile feel to it."

INSIDE:The multi-touch grid senses your fingers, the optical sensor works like any other mouse and the microswitch at the front is the mouse button

The shape of the mouse went through many different iterations and hundreds of protoypes, some with radically different designs; individual features that were popular with testers were combined into the final version. And the way that the touch surface on the mouse recognises gestures is based on how the hundreds of testers moved their fingers.

"We thought about how to define the gestures - move your finger this many millimetres up and you trigger the gestures. We decided to record a whole bunch of people doing them; we had folks with really giant hands, people with really small hands, male, female, left-handed, right-handed. We asked them to do things like 'put two fingers down and move up' and we used that to define how we recognise that gesture."

How many fingers make sense?

You scroll by dragging your fingers over the top surface but you can do more than scroll up and down; move your fingers from side to side and you scan scroll and pan across a window.

In a long document you can flick your finger up, down or across and then tap to stop scrolling when you get to the right page. Using two fingers to scroll controls your current window; move to fingers up to maximise a window or restore the previous size, two fingers down to minimise or restore a window - and two fingers to the side uses Aero Snap to fit to half the screen.

Use three fingers and you control all your windows; move three fingers up to open the revamped version of the task viewer in the IntelliPoint software, move three fingers down to minimise your windows and show the desktop.

"I'm a firm believer that the most dextrous finger on your hand is your thumb," jokes Benko - so you can swipe your thumb on the side of the mouse and move back and forward between web pages in the browser or slides in PowerPoint or images in Photo Gallery (it works in any app that has back and forward buttons).

TOUCHABLE:The grid of dots is laser etched into the Touch Mouse; the texture makes it easier to grip and less tiring to use

A little glowing indicator on screen shows you that you've used your thumb so you don't get confused (avoiding a problem that showed up in early testing when users sometimes didn't realise when their fingers were making a gesture) and this is a huge timesaver that immediately feels natural.

There aren't any gestures that use more fingers even though the mouse knows where they are. "We can see all five fingers", Benko explained, "but it's hard to keep even four fingers in place." The limitation is not what the mouse can detect but whether more complex gestures would be easy enough to use.

"We can actually detect 20 touch points," he told us, adding that his team wrote the underlying sensor code "and the actual underlying infrastructure is fairly similar to the code that's running in the Surface touch processing."

SIZE IS EVERYTHING:The gestures you can make on a mouse are limited by the size available - the Touch Mouse is big enough for most hands

The signal processing that the mouse does can encode lots of individual points on the touch surface at the same time but, as he put it, even though the touch surface goes almost to the very edge of the mouse "we have a real limitation with space and with your hand."

You can turn off gestures you don't use and switch the mouse to be left or right handed, but you can't make up your own gestures.

"We spent a lot of time optimising the gesture set so you can do these three different functions. Given the amount of time it took us to nail this experience," he suggests it might not be easy to design your own unique gesture that won't be mistaken for anything else. "You don't want to have the crosstalk problem: is it this gesture or is it that gesture?"

The future for the Touch Mouse

The team is thinking about more ways to use the multi-touch sensors, though. "We've thought about the authentication aspect," Benko told us enthusiastically; the way you move your fingers is often unique enough to identify you, so just gesturing on the mouse could be enough to log you in or load preferences for a different user if someone else uses your mouse.

"It would be really cool to do simple things - like we can totally detect handedness and we could switch the settings automatically. It would be really interesting - but at this point we're still nailing the basic experience. We want to come out with a great experience at launch."

Now that the Touch Mouse is almost done (it will be on sale in May), Benko's team is experimenting with what else they can do with multi-touch. "We've built some different mice with this type of sensor," he told TechRadar, mentioning one particularly intriguing idea we hope we get to see at CES 2012. "We've wrapped the capacitive surface around a pen and used it as a sensor."

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